Background Alcohol consumption is a well-known risk factor for
elevated ALT levels, but the role of cigarette smoking is unclear.

Methods We collected a cross-sectional sample of 6095 inhabitants
35 years or older in a community with hyperendemic hepatitis B and C virus
infections. We assayed levels of serum alanine aminotransferase (ALT),
hepatitis B surface antigen (HBsAg), and antihepatitis C virus antibody
(anti-HCV). Multivariate logistic regression was performed to determine
the factors for elevated ALT levels (40 U/L) among people with different
hepatitis infection statuses.

Results Prevalence of elevated ALT levels in individuals who were
seronegative for both infections or seropositive for HBsAg or anti-HCV
was 3.9%, 11.1%, and 30.8%, respectively. Subjects with elevated ALT levels
were more likely to be seropositive for anti-HCV, male, and seropositive
for HBsAg; to drink alcohol; to smoke; and to have undergone blood transfusion
(P<.05). An association was found between elevated ALT levels and the
consumption of cigarettes and alcohol among anti-HCVseropositive
subjects. In multivariate logistic analyses, alcohol consumption (odds
ratio [OR], 2.2; 95% confidence interval [CI], 1.2-4.1) and smoking (OR,
1.8; 95% CI, 1.1-2.7) were significantly associated with elevated ALT
levels among anti-HCVseropositive subjects, but no such association
was found among HBsAg-seropositive subjects. The odds of elevated ALT
levels were 7 times higher (95% CI, 2.7-18.8) for the anti-HCVseropositive
patients who smoked 1 or more packs of cigarettes per day and frequently
drank alcohol than for those who did not.

Conclusions Smoking and alcohol consumption are independently
associated with elevated ALT levels among anti-HCVseropositive individuals
but not among HBsAg-seropositive individuals. Patients who are seropositive
for anti-HCV are strongly advised not to smoke and drink alcohol to reduce
the possible risk for aggravating the liver dysfunction.

From the A-Lein Community Health Center, Kaohsiung County, Taiwan (Dr
C.-S. Wang); the Institute of Public Health, Department of Medicine, Colleges
of Medicine (Drs C.-T. Wang and S.-T. Wang), the Institute of Public Health,
Division of Gastroenterology, Department of Internal Medicine (Dr Chang),
and the Department of Nuclear Medicine, College of Medicine (Dr Yao),
National Cheng Kung University, Tainan, Taiwan; and the Community Medicine
Research Center and Institute of Public Health, National Yang-Ming University,
Taipei, Taiwan (Dr Chou).